The residual stress distribution was studied by an analytical model, due to shot peening on the welding carbon steel surface layer. The initial welding residual stresses before shot peening were taken into consideration in this analytical model. The Hertzian elastic contact theory was used to get the elastic compression stress state after impact on the surface layer. The initial welding stress field and the shot peening stress field would superpose and the welding surface layer would yield based on the elastic-plastic evaluation, then the residual stress after shot peening can be achieved. The influence of initial welding residual stress on the stress distribution after shot peening was analyzed and discussed. A series of experiments were carried out and the residual stress on the welding surface was determined by X-ray diffractometer before and after shot peening. The calculation results of the analytical model are consistent with the experimental results. The critical shot velocities when welding surface layer yielded and reverse yielded were calculated. While the welded joint surface material reversely yielded, the maximum compressive residual stress would not obviously increase with the increase of shot velocity, the thickness of the compressive stress layer would be increased. Welding residual tensile stress can enlarge the thickness of the compressive stress layer at the same shot velocity when reverse yield appeared. The residual stress distribution was studied by an analytical model, due to shot peening on the welding carbon steel surface layer. The initial welding residual stresses before shot peening were taken into consideration in this analytical model. The Hertzian elastic contact theory was used to get the elastic compression stress state after impact on the surface layer. The initial welding stress field and the shot peening stress would would superpose and the welding surface layer would yield based on the elastic-plastic evaluation, then the residual stress after shot peening can be achieved. The influence of initial welding residual stress on the stress distribution after shot peening was analyzed and discussed. A series of experiments were carried out and the residual stress on the welding surface was determined by X-ray diffractometer before and after shot peening. The calculation results of the analytical model are consistent with the experimental results. The critical shot velocities when welding surface layer yielded and reverse yielded were calculated. While the welded joint surface material reversely yielded, the maximum compressive residual stress would not obviously increase with the increase of shot velocity, the thickness of the compressive stress layer would be increased. stress can enlarge the thickness of the compressive stress layer at the same shot velocity when reverse yield appeared.